The present invention relates to apparatus useful for treating respiratory gases. More particularly, the invention relates to such apparatus which include liquid traps which preferably are effective to protect one or more components of the apparatus from being contaminated by liquid passed to the apparatus.
During surgery and other medical procedures, a patient is frequently connected to an anesthesia machine or ventilator to provide respiratory gases to the patient. The respiratory gases passed to the patient are advantageously filtered, heated and/or humidified so that the gases entering the patient are of a suitable quality, temperature and humidity so as not to adversely impact the patient. Heat and moisture exchangers (HMEs) are often used to provide heat and humidity to the respiratory gases entering the patient. Typically, these HMEs are located so that respiratory gases from the patient pass through a tracheal tube into the HME, often including a fibrous or other gas permeable material, which accumulates or collects heat and moisture from the exhaled gases. A filter element, for example, an antimicrobial filter element, is often located in the HME to filter respiratory gases passing through the HME. During the inhaling of respiratory gases, for example, from a respiratory ventilator machine, the HME provides both heat and moisture to these respiratory gases prior to the gases entering the patient. Over a period of time, the HME is effective to maintain a certain level of temperature and humidity in the respiratory gases entering the patient.
Although such HMEs do perform effectively to provide at least some of the useful heat and humidity needed for respiratory gases under normal or steady state conditions, additional, needed treatments for the patient may cause adverse effects to the HMEs. One example of such an additional treatment is the use of saline or other aqueous liquids to loosen mucous secretions in the trachea of the patient. Mucous build-up is of particular concern in situations when the patient is an infant or neonate and/or in long term, for example, about six (6) hours or longer, use of a ventilator. Saline lavage is often used to counter such mucous build-up. Thus, saline or other aqueous solution is injected through a suction catheter which is inserted inside the tracheal tube to loosen mucous secretions in the trachea. If the clinician accidentally gets the aqueous solution sloshing back with an exhaled breath or does not suction it correctly in a timely manner, the liquid can fill up or block a good portion of the flow area of the HME and/or the HME's filter element, thereby drastically increasing the pressure required to pass respiratory gases back and forth. In this situation, the HME filter or entire HME may have to be replaced in order to effectively allow respiratory gases to pass to and from the patient. Such replacement can be disruptive and/or harmful to the patient and/or can cause additional clinician stress.
Respiratory gas circuits can include a humidifier and a filter located between the patient and the humidifier. Such circuits are of particular value in treating infants and neonates, for example, with lung volumes on the order of about 10 cubic centimeters. However, liquid water can condense in the tubing from the humidifier and be "blown" or carried to the filter, where such liquid can cause increased pressure drop, disadvantageously making for more difficult respiration.
It would be advantageous to provide apparatus by which respiratory gases can be effectively and reliably treated and which can be protected against liquid material interfering with such treatment and/or causing problems with the respiration of the patient.